Enantiomeric LC separation of metolazone on amylose based sorbent

Abstract

A simple, rapid and robust LC method was developed and validated for the enantiomeric separation of metolazone. The enantiomers of metolazone were resolved on a Chiralpak AD-H (amylose based stationary phase) column using a mobile phase consisting of Hexane: 2-propanol: Methanol: Acetic acid (80:10:10:0.2, v/v) at a flow rate of 1.0 mLmin-1. The resolution between the enantiomers was found to be not less than 3.0 in optimized method. The presence of acetic acid in the mobile phase played an important role, in enhancing chromatographic efficiency and resolution between the enantiomers. The developed method was extensively validated and proved to be robust. The calibration curve for enantiomers showed excellent linearity over the concentration range of 5mgmL-1 to 50mgmL-1. The limit of detection and limit of quantification for enantiomers were 0.05 and 0.16 mgmL-1, respectively. The proposed method was found to be suitable and accurate for quantitative determination of enantiomers in bulk drug substance.